1. Field of the Invention
This invention is directed to a retractable diving board which is mounted on the underside of a platform or deck, preferably the front deck of a pontoon boat, so it may also serve as a gangplank. In recent times, there has been a phenomenal increase in the number of man-made reservoirs and ponds made available for use as recreational facilities. The U.S. Army Corps of Engineers has created innumerable impoundments on the tributaries of every major United States navigable waterway for flood control. Large impoundments of water can now be found throughout all the Mississippi Basin, the Missouri, Cumberland and Tennessee, Santee-Cooper, Columbia, Potomac and many other river basins, extending even to the smallest of tributaries, not only to hold back water to prevent flooding of downstream population centers, but to provide water in drought periods to aid navigability and irrigation. The general policy has been to make these impoundments available for recreational use by the public. Swimming and diving and boating are the most popular uses for these bodies of water, and the manufacture and sale of pontoon boats for recreational use has grown because the shorelines of these flood control reservoirs fluctuate greatly, and it is difficult to provide permanent and stationary swimming and diving facilities. Private facilities are also controlled and limited. There is a greatly increased demand for recreational equipment, such as the pontoon boat, which is well suited for use on flood control reservoirs because it provides a stable and mobile platform from which to enjoy all the water sports now made available, including swimming and diving.
2. Description of the Prior Art
Diving has become a highly developed sport, and even an art form, as exemplified by the platform and three meter springboard diving competition of the Olympic Games. Many advances have been made in springboard construction and mounting over the years. For example, U.S. Pat. Nos. 3,862,755 and 4,049,263 show major advances in springboard construction from wood diving boards common forty to fifty years ago. The above patents describe an extruded metal, hollow core diving board and a specially constructed, fibre glass diving board, respectively. FIG. 1 of U.S. Pat. No. 4,049,263 shows the typical mounting of a diving board at water's edge with a fixed attachment at the inner end, and a movable fulcrum supporting the intermediate portion of the diving board. Spring characteristics are changed by moving the fulcrum forward towards the front end of the board to decrease flexibility and back towards the fixed attachment to increase flexibility.
Various auxiliary means have been proposed for enhancing the spring characteristics of shorter, stiffer springboards for use at home pools and locations where cost and space prevent the use of full-sized, conventionally mounted springboards. U.S. Pat. No. 3,804,405 describes a shorter, wooden board mounted on a specially designed spring base which is anchored at poolside.
U S. Pat. No. 3,767,193 is directed to a portable diving board which is telescopically mounted in a support frame which, in turn, is mounted on the top of a raft or other platform. This patent shows the diving board telescopically enclosed in a tubular member and mounted on the top surface of a raft by means of brackets. In order to clear the platform of the diving board, it is necessary to retract the board and detach it from the brackets and remove it from the area. The brackets are normally intended to remain, providing dangerous obstructions for an unwary person to trip over.
Mountz U.S. Pat. No. 4,722,109 describes a retractable ramp for trucks which includes parallel spaced rails extending longitudinally of the truck which are secured to the truck chassis. A ramp is movable longitudinally in the track formed by the rails. It does not appear from the description that Mountz intends the ramp to be supported by the channel members in use, because hooks are provided on the forward end of the ramp for insertion into the truck sill plate when the ramp is in use.